Coal-water dynamic contact angle testing device under variable pressure condition

Abstract

The utility model belongs to the technical field of coal-water contact angle testing, and particularly discloses a coal-water dynamic contact angle testing device under a variable pressure condition. Comprising a constant-temperature box, a transparent sealing box, a sealant screw cap, an objective table, a coal sample, a high-definition lens, a light source, a gas cylinder, a gas injection pressure control box, a digital display temperature and pressure control box, a solution mixer, a clamp holder, an electromagnetic stirrer, a bubble capturer, a one-way flow regulating valve, a vacuum pump, a pressure regulator, an electric valve, a flow sensor, a flow controller and a pressure sensor, the device comprises a desorption pressure control box, an electric valve, a flow sensor, a flow controller, a pressure sensor, a pressure regulator and a computer. The coal-water dynamic contact angle testing system under the variable-pressure condition is adopted, and after adsorption of a coal sample is balanced, different variable-pressure conditions are simulated by gradually reducing pressure; the actual conditions of coal mine gas occurrence can be more accurately simulated by controlling the gas desorption rate, so that the coal-water contact angle test is closer to the real condition.

Description

Technical Field

[0001] The utility model relates to the technical field of coal-water contact angle testing, in particular to a coal-water dynamic contact angle testing device under variable pressure conditions. Background Art

[0002] Mine dust disasters seriously threaten the life, health and safety of coal miners and coal production safety. Coal seam water injection, as a key dust prevention measure, can increase the moisture content of coal and inhibit the generation of dust when coal is crushed. Coal seam water injection wetting is a long-term, continuous and dynamic process. It is necessary to analyze the dynamic wetting process of gas-containing coal from the perspective of exploring methods to promote the wetting effect of coal water.

[0003] During coal mining, the temperature and pressure conditions of the coal seam change dynamically, and the coal seam often contains different types of gases. Pre-adsorbing gas on coal samples can simulate the real environment of coal seam water injection under gas atmosphere. On the one hand, gas molecules are adsorbed on the surface of coal, changing the polarity and charge distribution of the coal surface, thereby affecting the wetting behavior of water molecules on the coal surface. On the other hand, the gas inside the coal body will occupy the pores and cracks of the coal, reducing the pore volume and specific surface area of ​​the coal, thereby reducing the wetting properties of the coal. When the coal adsorbs gas to equilibrium, the gas molecules in the coal body will reach a dynamic equilibrium state with the surface of the coal body. At this time, the degassing operation can break the equilibrium state by reducing the gas pressure outside the coal body, prompting the gas molecules inside the coal body to migrate to the outside, thereby reducing the gas pressure inside the coal. The coal-water contact angle test device and method under variable pressure conditions are of great significance for studying the surface properties of coal and the changing laws of its wetting behavior under different pressures.

[0004] Pressure is one of the important factors affecting wettability. Gas desorption will change the gas pressure and composition inside the coal sample, affect the surface properties of the coal sample, and further affect the wettability of the coal sample surface. However, the existing wetting angle test device is carried out under constant pressure conditions, and it is impossible to observe the change law of the wetting angle under variable pressure conditions.

[0005] Chinese patent application number CN202321320938.2 discloses a controllable temperature and pressure dynamic coal-water contact angle test device under different gas environments, which includes: a constant temperature box, a sealed box is provided in the constant temperature box, the top port is sealed and installed with a sealant screw cap, a dynamic angle controller is provided in the sealed box, and a coal sample is placed on the top of the dynamic angle controller, and a high-definition lens and a light source generator are respectively provided on the left and right sides of the sealed box; a beaker, the beaker is fixed to the sealed box by a clamp, and an electromagnetic stirrer is provided above the beaker. It mainly realizes the dynamic contact angle test of coal and water under constant pressure conditions in different gas environments and temperatures, and cannot observe the change law of the wetting angle under variable pressure conditions. Summary of the invention

[0006] The utility model aims to solve the deficiencies in the prior art and provide a coal-water dynamic contact angle testing device under variable pressure conditions.

[0007] In order to achieve the above-mentioned purpose, the utility model is implemented according to the following technical scheme:

[0008] A coal-water dynamic contact angle testing device under variable pressure conditions, comprising:

[0009] A constant temperature box, wherein a transparent sealed box is arranged in the constant temperature box, a top port of the transparent sealed box is sealed and installed with a sealant screw cap, a loading platform is arranged in the transparent sealed box, a coal sample is placed on the top of the loading platform, and a high-definition lens and a light source are arranged on the left and right sides of the transparent sealed box respectively;

[0010] Gas cylinders, two of which are provided, and both are arranged below the sealing box, and each of the gas cylinders is connected to the transparent sealing box and the gas injection pressure control box through a common gas pipeline;

[0011] A digital display temperature and pressure control box, which is installed on the front of the constant temperature box and controls the electromagnetic stirrer;

[0012] A solution mixer, the solution mixer is fixed on the transparent sealed box by a clamp, an electromagnetic stirrer is arranged in the solution mixer, a bubble catcher is installed at the bottom port of the solution mixer, the lower end of the bubble catcher is connected to one end of a water pipe, the other end of the water pipe passes through the sealant screw cap and extends to the top of the coal sample, and a one-way flow regulating valve is installed on the water pipe;

[0013] A vacuum pump, wherein the air inlet of the vacuum pump is connected to the top of the transparent sealing box through a pipeline;

[0014] A pressure regulator, the pressure regulator is connected to the top of the transparent sealed box through an air supply pipe, and an electric valve, a flow sensor, a flow controller and a pressure sensor are installed on the air supply pipe between the transparent sealed box and the pressure regulator in sequence;

[0015] A desorption pressure control box is installed on the front of the thermostatic box, and the desorption pressure control box controls and connects the electric valve, flow sensor, flow controller, pressure sensor and pressure regulator;

[0016] And a computer, wherein the computer is connected with the one-way flow regulating valve, the high-definition lens, the light source, the flow sensor, the flow controller, the pressure sensor, and the pressure regulator through a signal transmission line.

[0017] Furthermore, a transparent sealed box temperature control box and a transparent sealed box pressure control box are provided in the digital display temperature and pressure control box, and a desorption flow control box and a desorption pressure control box are provided in the desorption pressure control box.

[0018] Furthermore, the gas injection pressure control box is provided with a residual display and a pressure gauge, and a manual valve is installed on the gas transmission pipeline between the gas cylinder and the gas injection pressure control box.

[0019] Furthermore, a one-way valve is installed on the gas pipeline between the gas cylinder and the transparent sealing box.

[0020] Compared with the prior art, the utility model can obtain injection water solutions of different types and concentrations through a solution mixer, and the upper part is sealed with a sealing film to reduce the exposure time of the surfactant to the air; a microfluidic bubble catcher is added to reduce bubble generation, improve the stability of the water injection system, and reduce experimental errors; the pressure change inside the system is monitored and recorded in real time by a pressure sensor, and the pressure inside the system is precisely controlled by a pressure regulator, so as to study the change of the wetting angle under variable pressure conditions; at the same time, the inflow and outflow rates of the gas are controlled by a flow controller, so as to realize the regulation of the gas desorption rate; the pressure and flow changes in the desorption process are monitored in real time by a data acquisition system, and the data are fed back to the control system; the control system automatically adjusts the set values ​​of the pressure regulator and the flow controller according to the real-time monitored data and the target value, so as to realize the precise control of the pressure change; in summary, the utility model adopts a coal-water dynamic contact angle test system under variable pressure conditions, and after the coal sample is adsorbed in equilibrium, the pressure is gradually reduced to simulate different variable pressure conditions; by controlling the gas desorption rate, the actual conditions of coal mine gas storage can be more accurately simulated, so that the coal-water contact angle test is closer to the actual situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the utility model.

[0022] Figure 2 The utility model is a test flow chart of the device using the present utility model. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. The specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0024] like Figure 1 As shown, this embodiment exemplarily shows a coal-water dynamic contact angle test device under variable pressure conditions, comprising:

[0025] A constant temperature box 2, a transparent sealed box 10 is arranged in the constant temperature box 2, a top port of the transparent sealed box 10 is sealed with a sealant screw cover 9, a loading platform 11 is arranged in the transparent sealed box 10, and a coal sample 12 is placed on the top of the loading platform 11, and a high-definition lens 13 and a light source 14 are respectively arranged on the left and right sides of the transparent sealed box 10;

[0026] Gas cylinders 22, two gas cylinders 22 are provided, and both gas cylinders 22 are arranged below the sealed box 10. Each gas cylinder 22 is connected to the transparent sealed box 10 and the gas injection pressure control box 24 through a common gas pipeline; a one-way valve 21 is installed on the gas pipeline between the gas cylinder 22 and the transparent sealed box 10 to prevent the gas from being output in both directions and thus causing danger;

[0027] A digital display temperature and pressure control box 3 is installed on the front of the constant temperature box 2, and the digital display temperature and pressure control box 3 controls the electromagnetic stirrer 23; a transparent sealed box temperature control box 26 and a transparent sealed box pressure control box 27 are arranged in the digital display temperature and pressure control box 3, and a desorption flow control box 28 and a desorption pressure control box 29 are arranged in the desorption pressure control box 4;

[0028] A solution mixer 5, the solution mixer 5 is fixed on a transparent sealed box 10 through a clamp 8, an electromagnetic stirrer 23 is arranged in the solution mixer 5, a bubble catcher 6 is installed at the bottom port of the solution mixer 5, the lower end of the bubble catcher 6 is connected to one end of a water pipe, the other end of the water pipe passes through a sealant screw cap 9 and extends to the top of the coal sample 12, and a one-way flow regulating valve 7 is installed on the water pipe;

[0029] A vacuum pump 20, the air inlet of the vacuum pump 20 is connected to the top of the transparent sealing box 10 through a pipeline;

[0030] The pressure regulator 19 is connected to the top of the transparent sealed box 10 through an air supply pipe. The electric valve 15, the flow sensor 16, the flow controller 17 and the pressure sensor 18 are installed on the air supply pipe between the transparent sealed box 10 and the pressure regulator 19 in sequence. The pressure regulator 19 adjusts the intake or exhaust to achieve precise control of the internal pressure of the system;

[0031] The desorption pressure control box 4 is installed on the front of the thermostatic box 2. The desorption pressure control box 4 controls and connects the electric valve 15, the flow sensor 16, the flow controller 17, the pressure sensor 18 and the pressure regulator 19. The gas injection pressure control box 24 is provided with a residual display 32 and a pressure gauge 31. A manual valve 30 is installed on the gas pipeline between the gas cylinder 22 and the gas injection pressure control box 24.

[0032] And a computer 1, wherein the computer 1 is connected to the one-way flow regulating valve 7, the high-definition lens 13, the light source 14, the flow sensor 16, the flow controller 17, the pressure sensor 18, and the pressure regulator 19 through a signal transmission line 25.

[0033] like Figure 2 As shown, when using the above device for testing, the specific steps are as follows:

[0034] 1) Conduct a tightness test on the device before the experiment;

[0035] 2) Place the dried coal sample 12 in a transparent sealed box 10, turn on the high-definition lens 13 and the light source 14 through the computer 1, manually adjust the position of the coal sample 12, manually tighten the sealed box after adjustment, and evacuate the transparent sealed box 10 through the vacuum pump 20;

[0036] 3) Select the injection gas pressure through the gas injection pressure control box 24 and inject gas into the transparent sealed box 10, and close the manual valve 30 when the gas pressure in the transparent sealed box 10 reaches the preset pressure;

[0037] 4) Pour the prepared solution into the solution mixer 5 and turn on the stirrer 23 to mix it thoroughly, and at the same time set the required temperature of the thermostat, wait for the temperature in the thermostat to reach the preset constant temperature state, and the coal sample fully adsorbs the injected gas;

[0038] 5) Observe the pressure in the sealed box pressure control box 27 and use the real-time display to monitor the pressure in the transparent sealed box 10 in real time;

[0039] 6) The amount of solution dripped in is precisely controlled by regulating the one-way flow regulating valve 7 through the computer 1;

[0040] 7) The gas outflow rate is preset through the desorption flow control box 28, the gas outflow pressure is preset through the desorption pressure regulating box 29, the electric valve 15 is opened, and the pressure in the sealing box is gradually changed. The computer 1 records the process with high-definition video to observe the dynamic changes of the wetting angle of the droplets on the surface of the coal sample 12 under different pressures.

[0041] The technical solution of the present utility model is not limited to the above-mentioned specific embodiments, and all technical variations made according to the technical solution of the present utility model fall within the protection scope of the present utility model.

Claims

1. A coal-water dynamic contact angle test device under variable pressure conditions, comprising: A constant temperature box, wherein a transparent sealed box is arranged in the constant temperature box, a top port of the transparent sealed box is sealed and installed with a sealant screw cap, a loading platform is arranged in the transparent sealed box, a coal sample is placed on the top of the loading platform, and a high-definition lens and a light source are arranged on the left and right sides of the transparent sealed box respectively; Gas cylinders, two of which are provided, and both are arranged below the sealing box, and each of the gas cylinders is connected to the transparent sealing box and the gas injection pressure control box through a common gas pipeline; It is characterized by further comprising: A solution mixer, the solution mixer is fixed on the transparent sealed box by a clamp, an electromagnetic stirrer is arranged in the solution mixer, a bubble catcher is installed at the bottom port of the solution mixer, the lower end of the bubble catcher is connected to one end of a water pipe, the other end of the water pipe passes through the sealant screw cap and extends to the top of the coal sample, and a one-way flow regulating valve is installed on the water pipe; A digital display temperature and pressure control box, which is installed on the front of the constant temperature box and controls the electromagnetic stirrer; A vacuum pump, wherein the air inlet of the vacuum pump is connected to the top of the transparent sealing box through a pipeline; A pressure regulator, the pressure regulator is connected to the top of the transparent sealed box through an air supply pipe, and an electric valve, a flow sensor, a flow controller and a pressure sensor are installed on the air supply pipe between the transparent sealed box and the pressure regulator in sequence; A desorption pressure control box is installed on the front of the thermostatic box, and the desorption pressure control box controls and connects the electric valve, flow sensor, flow controller, pressure sensor and pressure regulator; And a computer, wherein the computer is connected with the one-way flow regulating valve, the high-definition lens, the light source, the flow sensor, the flow controller, the pressure sensor, and the pressure regulator through a signal transmission line.

2. The coal-water dynamic contact angle test device under variable pressure conditions according to claim 1, characterized in that: The digital display temperature and pressure control box is provided with a transparent sealed box temperature control box and a transparent sealed box pressure control box, and the desorption pressure control box is provided with a desorption flow control box and a desorption pressure control box.

3. The coal-water dynamic contact angle test device under variable pressure conditions according to claim 1, characterized in that: The gas injection pressure control box is provided with a residual display and a pressure gauge, and a manual valve is installed on the gas transmission pipeline between the gas cylinder and the gas injection pressure control box.

4. The coal-water dynamic contact angle test device under variable pressure conditions according to claim 1, characterized in that: A one-way valve is installed on the gas pipeline between the gas cylinder and the transparent sealing box.

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